MySQL Server Full Table Scan Percent Monitor Monitor

  • ID:  Microsoft.MySQLServer.ManagedServer.Unix.FullTableScanPct.Monitor
  • Description:  MySQL Server Full Table Scan Percent Monitor
  • Target:  Monitored MySQL Server (Linux)
  • Enabled:  On Standard Monitoring

Operational States

Name State Description
Under Threshold Success Under Threshold
Over Warning Threshold Warning Over Warning Threshold
Over Error Threshold Error Over Error Threshold

Overridable Parameters

Parameter Name Default Value Description Override
Interval 300 Interval in seconds
Number of Samples 3 Number of Samples
Warning Threshold 80 Warning Threshold
Error Threshold 95 Error Threshold

Alert Details

Monitor State Message Priority Severity Auto Resolution
Over Warning Threshold (Warning) MySQL Server Full Table Scans Medium Match Monitor Health Yes

Run As Profiles

Name
Default

Monitor Knowledgebase

Summary

The percent of full table scans made in the MySQL Server. Full table scan are when the server sequentially checks each row of the table for the validity of a condition. Full table scans can occur frequently on tables with a low number of rows. The monitor threshold is analyzed against an average of values returned in polls to the agent where the Number of Samples parameter controls the number of samples included in the calculation of the average.

Causes

An unhealthy state indicates the percentage of full table scans is high. Full table scans can occur on tables with fewer than 10 rows or a short row length. Full table scans can also occur when comparing indexed columns with constant values.

Resolutions

To address high percent of table scans try the following:

  • Optimize the MySQL query that are running full table scans

  • Use MySQL command “ANALYZE TABLE tbl_name” to update key distributions

  • Use MySQL option in command “FORCE INDEX” to manually opt out of the MySQL optimizer for the given index

  • Change the variable ‘max_seeks_for_key’ to a value that reflects needed lookups to retrieve data.

External References
This monitor does not contain any external references.

See Also for Open Source Software Preview Management Pack


Downloads for Open Source Software Preview Management Pack

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